Home made gauge to measure tp angle

[lucian]

Here is a gauge made from sheet copper to accurately verify the tp angle on my 1200 griso. The width is trimmed to the id of the tb and the end trimmed to the angle of the throttle plate. When checked with a protractor, low and behold it measured 4.8 degrees off 0, on my right unmolested side, the left side with the sacred screw(which had been buggered) was slightly off and easy to correct with this gauge . A flashlight pointed below the gauge makes it easy to ensure accuracy as light will leak between the throttle plate and the gauge if the fit is not perfect. What I learned is that even the tiniest of adjustments to the stop screw will make a drastic difference in the throttle plate position. Dropping the throttle link rod ensures individual set up and then adjusting the bellcrank screw if necessary to reconnect the rod. granted a flow bench would more accurately measure slight flow differences, but this at least puts you mechanically at the same start point. As it turns out my sacred screw was out about 1/4 turn and the bike is now idling perfect and running beautifully. When finished i checked the tps with guzzi diag and it was spot on 4.8 and just reset self learners. Idle balance needed a slight adjustment to the left air bleed and that was it.

[RinkRat II]

  Very Clever! Restores my faith in rocket scientists.
   
    Paul B

[Xlratr]

That is very neat! Well done.


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[lucian]

Here is an accurate plan if anyone has the same dilemma. It would be interesting to know how consistent these tb settings are. All that needs to be done is to pull the injectors, intake manifolds and couplings. About 8 screws and 4 clamps, real easy to do without removing the tb's.

[guzzisteve]

Well, you won't find that tool at your local Guzzi dealer. How long & on the clock @ $85 an hr.
A must have for those who like to tinker!!

[lucian]

Well, you won't find that tool at your local Guzzi dealer. How long & on the clock @ $85 an hr.
A must have for those who like to tinker!!

 :laugh:well at that rate you all owe me $14.166666 as it took about ten minutes to make.

[tris]

Damn that's neat

I know that the sacred screw on my B11 has been messed before I got the bike and it's somewhere close to where it should be but at least I can check with this.

Am I right in saying that if the connection rod between the two TBs hasn't been touched I can use this tool to make both sides the same by moving the sacred screw?

[lucian]

Damn that's neat

I know that the sacred screw on my B11 has been messed before I got the bike and it's somewhere close to where it should be but at least I can check with this.

Am I right in saying that if the connection rod between the two TBs hasn't been touched I can use this tool to make both sides the same by moving the sacred screw?

 I am not sure if your b11 has the same tb's  but surely the same principles would apply as far as making a gauge to check for identical throttle plate angles.

You CANNOT use the sacred screw to adjust a difference in throttle plate angles as doing so will move both simultaneously.

You must first drop the link rod off one side at the ball connection and then use the gauge to determine if both plates are at the same angle when they are closed against their stops.

Make the gauge to fit your un messed with side and you can then compare that with the opposite side  Once you have made the gauge check it with a protractor to make sure the plate angle is at the factory spec. ( in my case 4.8 degrees) if it is, then you can then check the other side and adjust as necessary to align the throttle plate with the gauge via the stop screw( sacred screw)

You may then need to adjust the link rod by adjusting the Bellcrank screw ( not the threaded rod ends) until perfect alignment with the ball and socket on the rod end is achieved

It is a must to have guzzi diag or similar to be able to check and reset your tps values and self learners before and after.

[redrider]

Before FI, throttle plate settings for CV carbs were checked with feeler gauges. So what is the gap between the TB wall and plate surface?

[lucian]

Before FI, throttle plate settings for CV carbs were checked with feeler gauges. So what is the gap between the TB wall and plate surface?

At 4.8 degrees there is no measurable gap , I even placed a flash light inside the intake side of the tb and no light at all leaked past the throttle plate when viewed from the out flow side. All idle air is supplied via the stepper and air bleed ports which are visible in the second photo. The flow bench balancing therefore must be done on greater throttle openings.My theory is that the motor itself becomes a flow bench when running and as long as the throttle plates are both at the factory angle when closed( in this case 4.8 degrees) and if the valves are properly adjusted and there are no other mechanical imbalances, then the tb balance at 3000 rpm and at idle operation will tune out any slight remaining imbalance in regards to intake flow. The important thing is that the tps reset to the ecu is performed when the base throttle plate position is as close as possible to physical 4.8 degrees as was intended.

[tris]

At 4.8 degrees there is no measurable gap , I even placed a flash light inside the intake side of the tb and no light at all leaked past the throttle plate when viewed from the out flow side. All idle air is supplied via the stepper and air bleed ports which are visible in the second photo. The flow bench balancing therefore must be done on greater throttle openings. My theory is that the motor itself becomes a flow bench when running and as long as the throttle plates are both at the factory angle when closed( in this case 4.8 degrees) and if the valves are properly adjusted and there are no other mechanical imbalances, then the tb balance at 3000 rpm and at idle operation will tune out any slight remaining imbalance in regards to intake flow. The important thing is that the tps reset to the ecu is performed when the base throttle plate position is as close as possible to physical 4.8 degrees as was intended.

Its interesting that you should say that as my head had be going along similar lines to fix my issue - specifically

On my B11
a) the sacred screw is on the LH throttle body (there is no adjustment on the RH TB)
b) the relative position of the RH butterfly to the LH butterfly is defined by the length of the connecting rod.
c) on my B11 (YMMV) the sacred screw has been moved but the rod length has not

Therefore if the rod is untouched then the closed position of both RH & LH butterflies is solely defined by the position of the sacred screw.

So my thoughts to fix goes like this.

To start with you need the valves and the like correctly adjusted and a functioning idle control valve

Then with a warmed up engine,
a) temporarily isolate the air supply to the ICV either by a valve or someway plugging the air supply to it within the air filter
b) start the engine and adjust the idle speed using the sacred screw to the 1100 +/- 100 RPM (my B11 setting)
c) stop engine and remove the temporary plug
d) Reset TPS setting via GuzziDiag
e) when you restart the engine then the ECU and specifically the ICV will take care of the rest

SIMPLES - but I bet its not

This hypothesis only holds water if the connecting rod has not been touched as otherwise there are too many variables

PS I'd love to use a Faroarm to get all the dimensions on a TB and then model it in CAD and see what angle the butterfly to choke diameter interface naturally is

[lucian]

which side is the tps located on on the B11?  And to reiterate, the sacred screw will move both plates together and will not correct any differences between the two throttle plate angles. The bellcrank screw will in effect, change the length of the link rod and therefor the relation of the plate angles. I would think also that both sides would have a stop screw, on mine the right side is hiding way beneath the tb.

[tris]

TPS is on the RH TB

B11 only has the one stop (sacred) screw on the LH TB